One of the easiest ways to find exoplanets is using the transit method. It relies upon monitoring the brightness of a star which will then dim as a planet passes in front of it. It is of course possible that other objects could pass between us and a star; perhaps binary planets, tidally distorted planets, exocomets and, ready for it…. alien megastructures! A transit simulator has been created by a team of researchers and it can predict the brightness change from different transiting objects, even Dyson Swarms in construction.  51 Pegasi-b was the first exoplanet discovered in 1995 and it sparked the development of numerous ground-based and space-based instruments. The launch of the Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) in 2018 popularised the transit method, leading to the discovery of over 4,000 exoplanets. As instruments have become increasingly sensitive and precise, research has progressed from simply detecting exoplanets to studying their detailed characteristics. Illustration of NASA’s Transiting Exoplanet Survey Satellite. Credit: NASA’s Goddard Space Flight Center Transit photometry has uncovered signatures of many interesting phenomena beyond the detection of exoplanets and eclipsing binaries. This technique has been instrumental in identifying features such as star-spots, and signatures of tidal interactions between host stars and exoplanets leading to significant growth in the sub-field of Asteroseismology The study of transiting exoplanets and their timing variations has led to many discoveries. Non-transiting planets in distant solar systems have been found, orbital decay, disintegrating planets, exocomets and exomoon candidates has all been identified. Additionally, and perhaps of particular interest is that transit photometry has detected signals that have sparked interest in the search for technosignatures for the evidence of advanced civilizations. It is important to note that no technosignatures have been confirmed yet but such signatures would not arise form natural processes and would demonstrate the presence of intelligent life. The signatures would come from a wide range of astroengineering projects like Dyson Spheres (a theoretical shell surrounding a star to capture its energy output) or the newly conceptualised Dyson Swarms (habitable satellites and energy collectors that orbit the star in formation.  The research team led by Ushasi Bhowmick from the Indian based Space Application Centre has reported that they have developed a transit simulator that can not only generate light curves for exoplanets but also for any object of any size or shape! The simulation uses the Monte-Carlo technique that predicts all possible outcomes of an uncertain event. In this instance it can predict the light curve when an object of any shape or size transits across the disk of star.  Artist’s impressions of two exoplanets in the TRAPPIST-1 system (TRAPPIST-1d and TRAPPIST-1f). Credit: NASA/JPL-Caltech When the simulation was tested against actual exoplanet systems such as Trappist-1 it nicely predicted the light curve. It can also be used to model tidal distortions in binary star systems and even predict the light curve of non-natural objects such as the alien megastructures. The simulator has shown itself to be an invaluable method for understanding a wide range of transit phenomena.  Source : A General-Purpose Transit Simulator for Arbitrary Shaped Objects Orbiting Stars The post That’s No Planet. Detecting Transiting Megastructures appeared first on Universe Today.

Universe Today has had some incredible discussions with a wide array of scientists regarding impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, meteorites, radio astronomy, extremophiles, organic chemistry, black holes, cryovolcanism, and planetary protection, and how these intriguing fields contribute to our understanding regarding our place in the cosmos. Here, Universe Today discusses the mysterious field of dark matter with Dr. Shawn Westerdale, who is an assistant professor in the Department of Physics & Astronomy and head of the Dark Matter and Neutrino Lab at the University of California, Riverside, regarding the importance of studying dark matter, the benefits and challenges, how dark matter can teach us about finding life beyond Earth, the most exciting aspects about dark matter he’s studied throughout his career, and advice for upcoming students who wish to pursue studying dark matter. So, what is the importance of studying dark matter? “About 80% of the mass of all matter in the universe is dark matter, despite the fact that our (otherwise extremely successful) model of fundamental particle physics cannot explain what it is,” Dr. Westerdale tells Universe Today. “We can see the gravitational influence of dark matter in our own galaxy and throughout the entire structure of the observable universe. It leaves a clear imprint on all of our cosmological and astrophysical observations through these gravitational interactions, so we know it is there and it does a remarkable job of explaining what we see. But we have no idea what it actually is made of, and this is an essential part of understanding nature.” The term “dark matter” was first coined in 1906 by French mathematician and theoretical physicist, Dr. Henri Poincaré, to describe work from 1884 by the British mathematical physicist, Dr. William Thomson (Lord Kelvin), regarding velocities of stars and some potentially being dark bodies. Throughout the rest of the 20th century, dark matter became a focal point in hypothesizing the behavior of galaxies and galaxy clusters with countless studies being published from academia, including the California Institute of Technology, along with research organizations like the SETI Institute. Despite decades of research, including the hypothesis of “cold”, “warm”, and “hot” dark matter, this mysterious substance has yet to be observed. Therefore, what are some of the benefits and challenges of studying dark matter? Dr. Westerdale tells Universe Today, “We haven’t found it yet, but we have ruled out many models, and in doing so we have helped refine our understanding of nature by ruling out possible modifications to the Standard Model of particle physics. On a sociological level, the study of dark matter has led to many new technologies for detecting radiation. Some of these may lead to new quantum technologies, and others are being developed into new medical imaging devices, just to name a few examples.” The three methods for attempting to observe dark matter include direct detection, indirect detection, and laboratory experiments using a myriad of laboratories from several countries around the world, including the Large Hadron Collider, which is the world’s largest particle collider. Additionally, several ground- and space-based telescopes have conducted surveys to try and create dark matter maps, including NASA’s Hubble Space Telescope, the Canada-France-Hawaii Telescope, the VLT Survey Telescope, and the Subaru Telescope. But what are the most exciting aspects about dark matter that Dr. Westerdale has studied during his career? Dr. Westerdale tells Universe Today, “To me the most exciting aspect of dark matter research has been the magnitude of the question. We have such successful models of cosmology and particle physics, and yet for all the success of these models, we still don’t know what most of the universe is even made of or how it got here!” The study of dark matter comprises some of the most fundamental questions pertaining to cosmology, the nature of the universe, and our place in it. What is the universe made of? How did it form? How did galaxies form? How do galaxies behave the way they do? How has all of this led to us being here and writing articles about dark matter like this one? The answers to these questions continue to elude astrophysicists, cosmologists, and countless other scientists despite decades of research, experiments, models, and hypotheses. Dr. Westerdale tells Universe Today, “One of the fun challenges of dark matter detection is that we are looking for extremely rare interactions and so we have to go to extraordinary lengths to make our experiments as quiet as possible. We put our detectors in deep underground labs, up to a mile underground, to avoid noise from cosmic rays, and levels of radioactivity that are normally so low they cannot be measured can swamp the signals we’re looking for. It is an exciting challenge to confront these things in our research and figure out how to design detectors that can meet all of our goals.” Despite the lack of observing dark matter and confirming its existence, this nonetheless signals that the next generation of dark matter enthusiasts, whether they become astrophysicists, cosmologists, or come from other scientific backgrounds, will have their work cut out for them, with some possibly being the ones to confirm dark matter’s existence. Like nearly all scientific research trajectories, the study of dark matter involves constant collaboration between scientists from a myriad of backgrounds and expertise’s. Therefore, what advice can Dr. Westerdale offer to upcoming students who wish to pursue studying dark matter? Dr. Westerdale tells Universe Today, “Experimental dark matter physics requires a very large breadth of knowledge, and so don’t silo your studies — any physics, math, and engineering skills you learn will at some point be useful. Programming skills are especially important, as are learning statistics, chemistry, and other engineering skills. And when you encounter something new, take the time to learn how it works on a fundamental level — it will be worth it later on once you can see how it fits into the big picture.” Will we ever observe dark matter and how will it help us better understand our place in the universe in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! The post Dark Matter: Why study it? What makes it so fascinating? appeared first on Universe Today.

One of the most fundamental questions astronomers ask about an object is “What’s its distance?” For very faraway objects, they use classical Cepheid variable stars as “distance rulers”. Astronomers call these pulsating stars “standard candles”. Now there’s a whole team of them precisely clocking their speeds along our line of sight. What makes a classical Cepheid a “standard candle” in the darkness of the Universe? It’s that pulsation. Not only does a Cepheid grow larger in a regular rhythm, but its brightness changes over predictable periods of time. In the early 1900s, astronomer Henrietta Leavitt studied thousands of these stars. She found something pretty interesting: there’s a strong relationship between a Cepheid’s luminosity and its pulsation period. And that’s a useful relationship. When you compare a Cepheid’s luminosity to its pulsation period, you can derive the star’s distance. This relationship appears to be true for all known Cepheids. That’s why they’re considered an important part of the cosmic distance ladder. They’re the main benchmark for scaling the huge distances between galaxies and galaxy clusters. Types of Cepheids There are different “flavors” of Cepheids. The “classical” ones have pulsation periods ranging from a few days to a few months. They’re all more massive than the Sun and can be up to a hundred thousand times more luminous. Their radii can change pretty drastically during a cycle—some grow by millions of kilometers and then shrink. Type II Cepheids have pulsation periods between 1 and 50 days and are usually very old, low-mass stars. There are other types, including anomalous Cepheids with very short periods. Scientists also know about double-mode Cepheids with “heartbeats” that pulsate in two or more modes. Some pretty well-known stars are Cepheid variables. For example, Polaris—the well-known “North Star” is one, as is RR Puppis, Delta Cephei, and Eta Aquilae—all visible from Earth. Why these stars pulsate is still being studied but here’s a very basic look at their process. The core of the star produces heat which heats the outer layers. They expand, and then cool. Radiation is escaping, which makes the star appear brighter. The cooler gas contracts under gravity and makes the star look smaller and cooler. Of course, the devil is in the details, which is why astronomers want to know more about the processes these stars undergo. Polaris A (Pole Star) with its two stellar companions, Polaris Ab and Polaris B. Polaris itself is a Cepheid type variable star. Artists impression. Credit: NASA However, it turns out Cepheids are not exactly easy to study. For one thing, it’s tough to measure their pulsations and radial velocities accurately. In addition, some have companion stars and the presence of a nearby star complicates any measurements. For another thing, different instruments and measuring methods give slightly different results, which doesn’t help astronomers understand those stars any better. Precision Measurements of Cepheid Variables Measuring the intricacies of Cepheid pulsations requires spectroscopic techniques that can measure light from stars and break it down into its component wavelengths. That reveals a lot of data about a star, including its chemical makeup, temperature, and motions in space. Calibrated Period-luminosity Relationship for Cepheid variables. Courtesy Spitzer Space Telescope/IPAC. A worldwide consortium of astronomers led by Richard I. Anderson at Switzerland’s École Polytechnique Fédérale de Lausanne (EPFL) is measuring specific properties of classical and other Cepheids using two high-resolution spectrographs. One is called HERMES on La Palma in the northern hemisphere and the other is CORALIE in Chile. They both detected tiny shifts in the light of target Cepheids. Those shifts gave valuable information about the motions of the stars. “Tracing Cepheid pulsations with high-definition velocimetry gives us insights into the structure of these stars and how they evolve,” he said. “In particular, measurements of the speed at which the stars expand and contract along the line of sight—so-called radial velocities—provide a crucial counterpart to precise brightness measurements from space. However, there has been an urgent need for high-quality radial velocities because they are expensive to collect and because few instruments are capable of collecting them.” VELOCE is on the Job The team’s measurement project is called the VELOCE Project—short for VELOcities of CEpheids. It’s 12-year-long collaboration among astronomers and astrophysicists. Anderson began the VELOCE project during his Ph.D work at the University of Geneva, continued it as a postdoc in the US and Germany, and has now completed it at EPFL. According to Ph.D student Giordano Viviani, the data from the project are already enabling new discoveries about Cepheids. “The wonderful precision and long-term stability of the measurements have enabled interesting new insights into how Cepheids pulsate,” Viviani said. “The pulsations lead to changes in the line-of-sight velocity of up to 70 km/s, or about 250,000 km/h. We have measured these variations with a typical precision of 130 km/h (37 m/s), and in some cases as good as 7 km/h (2 m/s), which is roughly the speed of a fast walking human.” Uncovering New Details about these Pulsating Stars The VELOCE project’s precision measurements also revealed some strange facts about these stars. For example, there’s an interesting phenomenon called the Hertzsprung Progression. It describes double-peaked bumps in a Cepheid’s pulsations. Astronomers aren’t quite sure yet why these bumps occur. But, they could give some insight into the structure of Cepheid variables, particularly the so-called “classical” ones. Other Cepheids show very complex variability, and changes in their radial velocities are not always consistent with predicted periods, according to postdoctoral researcher Henryka Netzel. “This suggests that there are more intricate processes occurring within these stars, such as interactions between different layers of the star, or additional (non-radial) pulsation signals that may present an opportunity to determine the structure of Cepheid stars by asteroseismology,” Netzel said. As part of their study, the team also measured 77 Cepheids that are part of binary systems. One in three Cepheids “lives” in a binary system, and often those unseen companions are detectable by velocity measurements. Characterizing the different “flavors” of Cepheids and the intricacies of their pulsations has larger implications than determining their radial velocities and bumps in their periods, according to Anderson. “Understanding the nature and physics of Cepheids is important because they tell us about how stars evolve in general, and because we rely on them for determining distances and the expansion rate of the Universe,” Anderson said, noting that VELOCE is also providing a valuable “cross-check” with Gaia measurements. It’s on track to conduct a large-scale survey of Cepheid radial velocity measurements. Cross-checking with Gaia Additionally, VELOCE provides the best available cross-checks for similar, but less precise, measurements from the ESA mission Gaia. That spacecraft is on track to conduct the largest survey of Cepheid radial velocity measurements. Data from that mission provides a growing three-dimensional map of millions of stars in the Milky Way and beyond. It not only charts their positions but also their motions (including radial velocity), as well as temperatures and compositions. Combined with high-precision data from VELOCE about Cepheids, astronomers should soon be able to get a handle on stellar and galactic evolutionary history. For More Information High-precision Measurements Challenge the Understanding of CepheidsVELOcities of CEpheids (VELOCE) The post Cepheid Variables are the Bedrock of the Cosmic Distance Ladder. Astronomers are Trying to Understand them Better appeared first on Universe Today.

One proposal offers a unique method to directly image ExoEarths, or rocky worlds around nearby stars. It’s the holy grail of modern exoplanet astronomy. As of writing this, the count of known worlds beyond the solar system stands at 6,520. Most of these are ‘hot Jupiters,’ large worlds in tight orbits around their host star. But what we’d really like to get a look at are ‘ExoEarths,’ rocky worlds (hopefully) like our own. Now, a recent study out of the University of Paris, the European Southern Observatory (ESO) and the University of Cambridge entitled Exoplanets in Reflected Starlight with Dual-Field Interferometry: A Case For Shorter Wavelengths and a Fifth Unit Telescope at VLTI/Paranal suggests a method to do just that in the coming decade. This would involve one the most massive telescope complexes ever built: the Very Large Telescope. Based at Paranal Observatory in Chile, this array consists of four 8.2-metre telescopes working in concert via a method known as interferometry. The study advocates adding a fifth telescope, giving the VLT the capacity to see Jupiter-sized worlds shining directly in the host star’s light… and with a few key upgrades, the new and improved VLT could perhaps image ‘ExoEarths’ directly. Pioneering Dual-Field Interferometry Interferometry is the method of using superimposed waves collected from two telescopes to merge a signal into one image. This method allows for a resolution equivalent to the baseline between the two collecting instruments, bypassing the need for one enormous telescope. Long baseline radio interferometry can span continents, and there are plans to move the technique into space. Interferometry at visual wavelengths is a tougher proposition, one that’s just reaching its true potential. Dual Field Interferometry uses the technique to simultaneously focus on two narrow fields in context within a larger field. One field is centered on the host star, and one on the target exoplanet. This can then minimize (subtract) photon shot noise from the primary, allowing for a clear view of the target world. “With this technique, at the VLTI, we have a resolution equivalent to having a telescope of 130 meters,” lead author on the study Sylvestre Lacour (University of Paris) told Universe Today. “This allows us to distinguish the exoplanet’s light from the contamination by the stellar light, allowing to detect exoplanets very close to the star.” ESO’s Very Large Telescope (VLT) timelapse of Beta Pictoris b around its parent star. This young massive exoplanet was initially discovered in 2008 using the NACO instrument at the VLT.  The sequence tracked the exoplanet from late 2014 until late 2016, using the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) — another instrument on the VLT. “The term ‘dual’ in dual interferometry comes from the fact the we are observing at the same time the exoplanet and the star with the optical interferometer,” says Lacour. “This is necessary to be able to probe at the same time the phase of the stellar light and the phase of the exoplanet light, to be able to distinguish the two. By ‘phase’ I mean the phase of the electric field entering the interferometer.” The GRAVITY instrument at the VLTI in Paranal. Credit: ESO The Hunt for ExoEarths The method is already being applied to reveal nearby worlds. “We typically observe exoplanets at a few tens of parsecs,” says Lacour. “They are massive exoplanets, more massive than Jupiter (between 4 and 10 Jupiter masses), and they are young, less than 50 million years (old). You can look for the results for the GRAVITY collaboration, operating the GRAVITY instrument at Paranal.” One key technique used to overcome the effects of ‘shot noise’ is what’s termed as ‘apodization’. “Apodization is a way to decrease the contamination of the stellar light entering into our interferometer,” says Lacour. “It is similar to adding a coronagraph.” Apodization makes ground-based systems such as the VLTI viable in terms of exoplanet science and direct detection. Other efforts such as the European Space Agency’s Proba-3 space telescope launching later in 2024 will use a free flying coronagraph to directly image exoplanets. A pro to this method is it can characterize orbits within a few Astronomical Units from their host star. Other techniques observe planets very close in, or very far out. The downside of the method is that it’s a very difficult technique, right on the grim edge of what’s currently possible with existing telescopes. An artist’s conception of the E-ELT telescope. Credit: Swinburne Astronomy Productions/ESO The Future of Exoplanet Astronomy There’s already a good case for plans to extend the VLTI baseline to a fifth instrument. This includes direct imaging for worlds known orbiting around nearby stars to include Proxima Centauri B and Tau Ceti e. Lessons learned from the VLTI could also work for the Extremely Large Telescope, which may see first light in 2028. An artist’s conception of Tau Ceti e, a possible ‘ExoEarth’ in the habitable zone. Ph03nix1986/Wikimedia Commons/CCA 4.0 It’ll be exciting to see more nearby worlds revealed by this technique in the coming decade. The post Existing Telescopes Could Directly Observe ‘ExoEarths…’ with a Few Tweaks appeared first on Universe Today.

Every year on June 30, Asteroid Day marks the anniversary of a meteor airburst in 1908 that leveled hundreds of square miles of Siberian forest land. But a more recent meteor blast — and a new plan for getting advance warning of the next one — is receiving some added attention for this year’s Asteroid Day. The first-ever Schweickart Prize, named in honor of Apollo 9 astronaut Rusty Schweickart, is going to a researcher who has proposed a system for spotting potentially threatening asteroids coming at us from a difficult-to-monitor zone between Earth and the sun. It was just such an asteroid that blew up over the Siberian city of Chelyabinsk in 2013, spraying debris that injured about 1,500 people and caused an estimated $33 million in property damage. The proposal from astronomy Ph.D. student Joseph DeMartini calls for setting up a consortium of ground-based observatories, anchored by the Vera C. Rubin Observatory in Chile, to focus on the twilight sky just after sunset and just before sunrise. Those are the times of day when astronomers have the best chance of finding sunward near-Earth objects (NEOs) that spend much of their time within Earth’s orbit. “It’s a very interesting proposal that we hope gets picked up,” Rusty Schweickart said. DeMartini’s concept for what he calls the Sunward NEO Surveillance and Early Twilight detection collaboration — or SUNSET for short — was judged the top entry in the competition for the Schweickart Prize. The award, which is a program of the California-based B612 Foundation, recognizes graduate students who come up with innovative ideas for planetary defense. As the prize winner, DeMartini will receive a $10,000 cash prize and a trophy topped by an authenticated meteorite during a ceremony on June 29 at the Chabot Space & Science Center in Oakland, Calif. “The thing that actually got me to put my idea forward was the meteorite fragment,” said DeMartini, who’s earning his Ph.D. from the University of Maryland. “I saw that and I was like, ‘Oh my gosh, I really want that.’ But maybe that’s just me being an asteroid nerd.” DeMartini said the idea behind SUNSET came out of discussions he had with a colleague about the asteroid that sparked the Chelyabinsk blast. “The reason we didn’t have any warning was because it came from the direction of the sun, and we can’t look in the direction of the sun,” he said. “That got me thinking, ‘Wow, that’s a region we should really monitor.'” It turns out that the Rubin Observatory is looking into conducting just such a monitoring effort after it gets up and running next year. DeMartini suggests that the SUNSET network could augment the sightings made at the Rubin Observatory, and confirm the precise orbits traced by sunward NEOs. “If these other telescopes know where to point in advance, then they can follow up on anything that Rubin discovers in a night, and then we can get these confirmations more easily,” he said. The current focus of DeMartini’s research actually has to do with a different topic: numerical simulations of asteroid surfaces and interiors, and how close encounters with Earth might change those values. But when his faculty adviser told him about the Schweickart Prize, DeMartini decided to enter the competition. From left: Apollo 9 astronaut Rusty Schweickart; the Schweickart Prize, topped by a meteorite; and the first winner of the prize, University of Maryland astronomer Joseph DeMartini. (Credits: RustySchweickart.com; Christopher Che via SchweickartPrize.org; University of Maryland) It should come as no surprise that Rusty Schweickart himself was one of the judges. In his post-NASA career, he has focused on the challenges of asteroid threat detection and mitigation. He’s the founder and past president of the Association of Space Explorers, which took up the NEO threat as one of its causes. He’s also a co-founder of the B612 Foundation, which raises awareness about planetary defense, and a co-founder of Asteroid Day as well. “What we’re talking about here in planetary defense is having the capability to ever so slightly, but critically, reshape the solar system to enhance the future of life on Earth,” Schweickart said. “To prevent this existential threat — that is what I’ve dedicated the last 20 years of my life to bringing about.” Thanks in part to a congressional mandate, more than 90% of the biggest near-Earth asteroids, exceeding a kilometer (0.6 mile) in diameter, are thought to have been identified and are being tracked. That’s the kind of asteroid that wiped out the dinosaurs roughly 66 million years ago. “But it’s the ones that are the city-killers — the 40- to 50-meter-diameter guys — that you can’t see until they’re pretty close to the Earth,” Schweickart said. “That means looking interior [to Earth’s orbit] is going to be more productive than looking exterior.” DeMartini’s proposal was selected as the winner because it addresses one of the biggest gaps in asteroid monitoring, and because it takes advantage of advances in observational firepower. The Rubin Observatory’s Survey Cadence Optimization Committee, or SCOC, says doing the kind of twilight sky survey that DeMartini discusses in his SUNSET proposal would be “scientifically compelling.” It recommends starting such a survey soon after the telescope begins science operations next year. “We currently are simulating the effect of adding low-solar-elongation observations during the start and end of twilight, spending about 15 to 20 minutes of the start and end of about a quarter of the survey nights observing at high airmass toward the sun,” Lynne Jones, an astronomer who’s part of the Rubin team, said in an email. “This gives us the opportunity to detect asteroids interior to the Earth, even down to parts of the sky which are closer than 40 degrees from the sun.” This time-lapse simulation illustrates how the Rubin Observatory could focus on twilight zones at the start and end of a survey night. Credit: Lynne Jones / Aerotek / Rubin Observatory. DeMartini said the Rubin Observatory’s twilight survey campaign would be “step one” in his vision for the SUNSET collaboration. “The next bit, I suppose, would be networking. Hopefully, this event that I’ll be going to when I’m receiving the prize will be a good opportunity for that. And that’s something that B612 can really help with,” he said. “If it takes off, I don’t know what it looks like in 10 years. But my hope is that we’re safer because of it,” DeMartini added. Randy Schweickart, who is one of Rusty’s sons and the chair of the prize program’s judging committee, said he and other family members are committed to funding the Schweickart Prize for at least five years. “The hope is that — similar to the Astronaut Scholarship Foundation, which has expanded tremendously from its beginnings — there would be support from other sources as we move in time and are able to get more of the word out,” he said. Rusty Schweickart said that the prize is meant for more than astronomers. “The really toughest problems related to planetary defense are the governance issues — the non-technical, geopolitical and legal issues,” he said. “So, in the future, what we want to do is move more in that direction, and get law students, economics students, public-safety people, emergency-response people to be involved in this. Because in the end, they’re going to be very critical.” Schweickart, who’ll turn 90 next year, hopes the prize will carry on his legacy when he’s “pushing up daisies.” “It seems to me that that we have, as human beings, a special responsibility to do whatever we can to see that this evolutionary experiment that we’re having here on planet Earth continues,” he said. “I’m not quite sure why that’s the responsibility, but I think it is. And if so, I feel obligated to do what I could.” Scores of events have been scheduled around the world to mark Asteroid Day, including a two-day festival in Luxembourg. The award ceremony for the Schweickart Prize will take place at 3:30 p.m. PT June 29 at the Chabot Space & Science Center in Oakland, Calif. The event will feature a presentation by Rusty Schweickart, plus comments from NASA astronauts Steve Smith and Nicole Stott, and from YouTube space commentator Scott Manley. Click to purchase tickets. Founding Sponsors who have funded the Schweickart Prize program include Anousheh Ansari, Barringer Crater Company, B612 Foundation, Future Ventures, Geoffrey Notkin, Jurvetson Family Foundation, Meteor Crater, Randy Schweickart and Michelle Heng, and Rusty B. Schweickart and Joanne Keys. The post Happy Asteroid Day! Schweickart Prize Spotlights Planetary Defense appeared first on Universe Today.

Humanity is facing an atmospheric threat of our own device, and our internecine squabbles are hampering our ability to neutralize that threat. But if we last long enough, the reverse situation will arise. Our climate will cool, and we’ll need to figure out how to warm it up. If that day ever arises, we should be organized enough to meet the challenge. If there are other civilizations out there in the galaxy, one may already be facing a cooling climate or an ice age. Could we detect the greenhouse chemicals they would be purposefully emitting into their atmosphere in an attempt to warm their planet? New research in The Astrophysical Journal explains how the JWST or a future telescope named LIFE (Large Interferometer For Exoplanets) could detect certain chemicals in an exoplanet’s atmosphere that signal an intentional attempt to warm it. The title is “Artificial Greenhouse Gases as Exoplanet Technosignatures.” The lead author is Edward Schwieterman, Assistant Professor of Astrobiology at UC Riverside and a Research Scientist at Blue Marble Space Institute of Science in Seattle, Washington. “Atmospheric pollutants such as chlorofluorocarbons and NO2 have been proposed as potential remotely detectable atmospheric technosignature gases,” the authors write in their paper. “Here, we investigate the potential for artificial greenhouse gases, including CF4, C2F6, C3F8, SF6, and NF3, to generate detectable atmospheric signatures.” The first three are perfluorocarbons, potent and long-lived greenhouse gases (GHGs.) SF6 is Sulfur hexafluoride, and NF3 is Nitrogen trifluoride. They’re both greenhouse gases with global warming potentials 23,500 times greater and 17,200 times greater than CO2 over a 100-year period. These artificial GHGs could be a technosignature of a civilization actively trying to warm their planet. They’re long-lived, have low toxicities, and have low false-positive potential. They also occur only in small amounts naturally. Their presence indicates industrial production. “For us, these gases are bad because we don’t want to increase warming. But they’d be good for a civilization that perhaps wanted to forestall an impending ice age or terraform an otherwise-uninhabitable planet in their system, as humans have proposed for Mars,” said UCR astrobiologist and lead author Edward Schwieterman. These chemicals could persist in an atmosphere for up to 50,000 years, making them near ideal for a civilization facing a freezing future. “They wouldn’t need to be replenished too often for a hospitable climate to be maintained,” Schwieterman said in a press release. Unlike CFCs (chlorofluorocarbons), which damage the ozone layer, these chemicals are largely inert. Any civilization smart enough to engineer their atmosphere would avoid CFCs. CFCs also don’t last long in an oxygen atmosphere and wouldn’t be great technosignatures. “If another civilization had an oxygen-rich atmosphere, they’d also have an ozone layer they’d want to protect,” Schwieterman said. “CFCs would be broken apart in the ozone layer even as they catalyzed its destruction.” But from our ETI-seeking viewpoint, the best thing about the chemicals the researchers are studying is their prominent infrared signatures at extremely low concentrations. “With an atmosphere like Earth’s, only one out of every million molecules could be one of these gases, and it would be potentially detectable,” Schwieterman said. “That gas concentration would also be sufficient to modify the climate.” To understand these chemicals and their detectability, the research team simulated the atmosphere of TRAPPIST 1-f. This well-studied rocky exoplanet is in the habitable zone of a red dwarf star about 40 light-years away, making it a realistic observational target at that distance. This artist’s illustration shows the exoplanet TRAPPIST-1f, a potentially rocky Super-Earth orbiting in a red dwarf’s habitable zone. Image Credit: NASA/JPL-Caltech This study is based on the potential results of the LIFE telescope, which is still a concept. Its purpose is to examine the atmospheres of dozens of warm, terrestrial exoplanets. LIFE builds on telescope concepts from a couple of decades ago, like the European Space Agency’s Darwin spacecraft. Darwin wasn’t built, but the idea behind it was two-fold: to both find Earth-like exoplanets and to search for evidence of life. Darwin was conceived as an interferometer, and so is LIFE. LIFE would have four separate space telescopes acting as one. This artist’s illustration shows LIFE’s four telescopes and its central unit acting as an interferometer. Interferometers create a large and powerful “virtual telescope.” Image Credit: LIFE/ETH Zurich With LIFE, the GHGs would be easier to see than other standard biosignatures like O2, O3, CH4, and N2O. But unlike these chemicals, which can give false positives without a planetary context, the GHGs are more akin to technosignatures, which can be understood more independently from atmospheric chemistry. “In contrast to biosignatures, many technosignatures may provide greater specificity (less “false positive” potential), as many putative technosignatures have more limited abiotic formation channels when compared to biosignatures,” the authors explain in their research. These figures show some of the simulation transmission spectra from the research. The top panel shows how different concentrations of three of the GHGs show up in MIR spectrometry for a simulated Earth-like TRAPPIST 1-f planet. The bottom panel shows how different concentrations of NF3 show up. O3 is shown because it shows up in the same band. The black line is the atmospheric spectrum without the GHGs. The 100 ppm results are from observing the planet for 10 transits. Image Credit: Schwieterman et al. 2024. One desirable aspect of the search for these technosignature GHGs is that astronomers can find them as part of a general effort to study atmospheres. “You wouldn’t need extra effort to look for these technosignatures, if your telescope is already characterizing the planet for other reasons,” said Schwieterman. “And it would be jaw-droppingly amazing to find them.” These figures show some of the simulated emission spectra for the GHGs compared to Earth with no technosignatures. They also show some of the technosignatures at different PPM concentrations and Earth’s O3, CO2, and H20. The spectra are different than the transmission spectra. Image Credit: Schwieterman et al. 2024. This is not a futuristic scenario awaiting the development of new technology. We have the capability to do this soon, according to Daniel Angerhausen. Angerhausen is from the Swiss Federal Institute of Technology/PlanetS, a collaborating organization on LIFE. “Our thought experiment shows how powerful our next-generation telescopes will be. We are the first generation in history that has the technology to systematically look for life and intelligence in our galactic neighborhood,” said Angerhausen. This concept figure illustrates a hypothetical Earth-like inhabited planet terraformed with various combined abundances of artificial greenhouse gases C3F8, C2F6, and SF6 and its resulting qualitative MIR transmission (top) and emission (bottom) spectra. Image Credit: Sohail Wasif, UC Riverside/Schwieterman et al. 2024. “While all technosignature scenarios are speculative, we argue that it is unlikely fluorine-bearing technosignature gases will accumulate to detectable levels in a technosphere due only to inadvertent emission of industrial pollutants (or volcanic production),” the authors write. They also explain that before individual GHG technosignatures were identified, anomalous MIR or NIR absorption signatures “… would be consistent with the presence of artificial greenhouse gases in a candidate technosphere.” In their conclusion, they say that GHGs are viable technosignatures that can be found during routine exoplanet characterizations. “Both positive or negative results would meaningfully inform the search for life elsewhere,” they conclude. The post Could We Detect an Alien Civilization Trying to Warm Their Planet? appeared first on Universe Today.

Martin Vargic is a space enthusiast, author, and graphic artist from Slovakia. He created two new infographic posters that show almost 1600 exoplanets of different types and sizes. One is called Icy and Rocky Worlds, and the other is called The Exoplanet Zoo. Vargic has been interested in astronomy and space for as long as he can remember. When he was 10 years old, he used his family’s telescope to gaze at lunar craters, Jupiter’s moons, and Venus’s phases despite living in areas with lots of light pollution. “On the rare occasions I got to see a clear sky and the Milky Way I was astounded by the sheer amount of stars,” Vargic told Universe Today. In 2015, he devoured books on astronomy, cosmology, space exploration, and physics and created the first versions of what would eventually become these ambitious infographics. In 2019, after three years of work, Vargic published a visual book on the universe, astronomy, and space exploration called the “Curious Cosmic Compendium.” In the Compendium, “10 pages were solely dedicated to exoplanets, with their temperature ascending page-by-page until transitioning to brown dwarfs and red dwarf stars,” Vargic told Universe Today. All of that work led to these two new exoplanet infographic posters. This is “The Exoplanet Zoo,” one of two new exoplanet infographics from Slovak artist and space enthusiast Martin Vargic. Image Credit and Copyright: Martin Vargic. “With the help of scientific models and up-to-date information, this poster attempts to artistically visualize together over 1100 known exoplanets of all the different types we have discovered so far, arranged by the amount of heat they receive from their stars, comparing their relative sizes and providing a window to how they might look like,” Vargic explains on his website. The poster shows exoplanets in all their weird and wonderful forms. It shows PSR-B1620-26b, the oldest known exoplanet. This zoom-in of “The Exoplanet Zoo” shows the oldest known exoplanet, PSR B1620-26b. Image Credit and Copyright: Martin Vargic. It also shows WASP-12b, a scorching hot gas giant so close to its star that it’s warped into an egg shape. You can’t miss WASP-12b on “The Exoplanet Zoo.” It’s so close to its star that it’s warped into an egg shape. Image Credit and Copyright: Martin Vargic. “Finishing both infographics took about 6-7 months. I worked on both simultaneously while creating planetary textures and rendering the planets one by one,” Vargic told Universe Today. More detail from “The Exoplanet Zoo.” Eburonia is a gas giant about 134 light-years away. It takes fewer than five days to orbit its star and is named after a Belgic tribe called the Eburones. Image Credit and Copyright: Martin Vargic. “Data for both exoplanet infographics was gathered from three public exoplanet databases, The Extrasolar Planet Encyclopaedia, NASA Exoplanet Archive and ExoKyoto,” Vargic explained. The colours of the gas giant exoplanets are based on the Sudarsky Scale. It takes into account the various chemicals and temperatures of planetary atmospheres. Vargic also used existing exoplanet illustrations as a source. Detail from “The Exoplanet Zoo.” The planets get progressively hotter from left to right. This detail shows 55 Cancri e, the hottest known rocky exoplanet. Image Credit and Copyright: Martin Vargic. See Martin’s work, including high-resolution versions of his infographics, at halcyonmaps.com. The post Take a Look at These Stunning New Exoplanet Infographics appeared first on Universe Today.

Protecting the astronauts of the Artemis program is one of NASA’s highest priorities. The agency intends to have a long-term presence on the Moon, which means long-term exposure to dangerous radiation levels. As part of the development of the Artemis program, NASA also set limits to the radiation exposure that astronauts can suffer. Other hazards abound on the lunar surface, including a potential micrometeoroid strike, which could cause catastrophic damage to mission equipment or personnel. NASA built a team to design and develop a “Lunar Safe Haven” to protect from these hazards. Their working paper was released in 2022 but still stands as NASA’s best approach to long-term living on the lunar surface. The two hazards mentioned above provided the primary impetus for the design, but there are some nuances to them—in particular, radiation. Astronauts will experience two main types of hazardous radiation on the lunar surface: cosmic rays and solar eruptions.  Cosmic rays are the more insidious of the two. They have a high energy range, so a shielding material that might work well for higher-energy particles might not do so for lower-energy ones. Moreover, some high-energy particles can interact with shielding, causing even more damaging radiation further down its path. Essentially, this increases the radiation risk inside the shielding compared to outside. The order in which the radiative particles are dealt with is one of the critical design considerations for dealing with this dangerous phenomenon.  Lunar regolith can be hard to deal with, as Fraser discusses with Dr. Kevin Cannon. However, solar particle events (SPEs) are the more overtly dangerous of the two types of radiation. While rare, they can cause acute radiation sickness. Current astronauts must shelter in place inside a protected chamber on the ISS when these happen, and building something equivalent on the surface of the Moon is a necessity to ensure that astronauts don’t simply die of acute radiation poisoning within the first six months of arrival. With the problems to solve firmly in hand, the design team moved on to other considerations—like what the habitat inside the LSH would actually look like and how it would be built. Consideration of the habitat shape focused on one primary distinction—should the habitat be horizontal or vertical? The answer is vertical based on modeling the risk of radiation and micrometeoroid strikes. So, how do you build a structure around a vertical habitat on the Moon? You employ robots and remotely operated construction equipment. Other groups at NASA had been working on solutions like the Lightweight Surface Manipulation System (LSMS), essentially a large crane that can be constructed in lunar gravity, and the Lunar Attachment Node for Construction and Excavation (LANCE) – a bulldozer module designed to attach to the front of NASA’s Chariot exploration vehicle. Utilizing these ideas and other construction ideas, it’s possible to construct a protective dome of lunar regolith around a long-term habitat for the Artemis missions.  Fraser overviews the Artemis mission that LSH will attempt to help. Such a protective habitat has significant advantages over digging one into the ground, which requires moving a massive amount of regolith or utilizing lava tubes with indeterminate structural integrity. But that means the LSH must have an above-ground design. The team developed two separate design ideas – a parabolic arch and a “Round Cake” design using polyethylene. The first is self-explanatory, but the second looks more like a typical cylinder with the radiation and micrometeoroid-blocking polyethylene stored in “beans” at the top of the structure. This could be made of waste materials from the mission, such as discarded food packaging. Each design has advantages and disadvantages, and the team didn’t pick a final one as part of the paper. However, they did come up with a five-phase development process, from preparing the site in advance to living in interconnected habitats surrounded by regolith and protective shielding. Depending on the amount of automation involved and some real luck, those development phases could take anywhere from a few years to a few decades.  It remains to be seen if this system will be adopted as an official part of the Artemis program. But it serves a need of critical importance to humanity’s long-term existence on the Moon. If that is indeed NASA’s goal for the end of the 2030s, it would be good to consider how to start making the LSH a reality. Learn More:Wok et al. – Design Analysis for Lunar Safe Haven ConceptsMoses & Grande – Lunar Safe Haven Seedling StudyUT – What Could We Build With Lunar Regolith?UT – There are Four Ways to Build with Regolith on the Moon Lead Image:Artist’s depiction of the Parabolic Arc LSH in cutaway.Credit – Wok et al. The post Could A Mound of Dust and Rock Protect Astronauts from Deadly Radiation? appeared first on Universe Today.

As the most volcanic object in the Solar System, Jupiter’s moon Io attracts a lot of attention. NASA’s Juno spacecraft arrived at the Jovian system in July 2016, and in recent months, it’s been paying closer attention to Io. Though Io’s internal workings have been mostly inscrutable, images and data from Juno are starting to provide a fuller picture of the strange moon’s volcanic inner life. Io’s extreme volcanic activity stems from tidal heating caused by massive Jupiter and its powerful gravity. Some of the moon’s volcanoes spew out plumes of sulphur and sulphur dioxide as high as 500 km (300 miles) above its surface. Sulphur is also ever-present in its lava flows, which colour the moon’s surface in various shades of yellow, red, white, green, and black. Some of the lava flows extend up to 500 km (300 miles) along its surface. These features entice scientists to study the moon more thoroughly. One of Juno’s instruments is an imager and spectrometer that operates in the infrared. It’s called JIRAM (Jovian Infrared Auroral Mapper.) It was designed to, obviously, map Jupiter’s aurorae. But as Juno’s orbits have brought it progressively closer to Io, JIRAM is delivering high-quality images and data from the volcanic moon. “The observations show fascinating new information on Io’s volcanic processes.”Scott Bolton, Principal Investigator for Juno, SwRI In new research in Nature Communications Earth and Environment, a team of scientists present some new insights into the moon and its vigorous volcanic activity. The title is “Hot rings on Io observed by Juno/JIRAM.” The lead author is Alessandro Mura from the National Institute of Astrophysics—Institute of Space Astrophysics and Planetology, Rome, Italy. Italy provided the JIRAM instrument for the Juno mission. “We are just starting to wade into the JIRAM results from the close flybys of Io in December 2023 and February 2024,” said Scott Bolton, principal investigator for Juno at the Southwest Research Institute in San Antonio. “The observations show fascinating new information on Io’s volcanic processes. Combining these new results with Juno’s longer-term campaign to monitor and map the volcanoes on Io’s never-before-seen north and south poles, JIRAM is turning out to be one of the most valuable tools to learn how this tortured world works.” Io has many of what planetary scientists call ‘paterae.’ Paterae are irregular craters or complex craters with scalloped edges. They’re usually broad and shallow, and scientists have wondered if they hold lava lakes. Older observations of Io from NASA’s Galileo spacecraft were inconclusive, but new images from Juno and JIRAM have much higher resolution. In 2023, Juno came to within 13,000 km (8,100 miles) of Io’s surface, allowing JIRAM to capture greater detail. These images show more detail for a greater number of paterae, and the features the images reveal suggest that many of the craters have active lava lakes. “This new Juno/JIRAM data suggests that hot rings around paterae are a common phenomenon, and that they are indicative of active lava lakes,” the authors write in their paper. This graphic shows the infrared radiance of Chors Patera, a lava lake on Jupiter’s moon Io. The white ring is the hottest part of the patera, between 232 and 732 Celsius, where lava from the moon’s interior is exposed. The red/green inside the ring is likely a thick crust of molten material that’s -43 Celsius. Outside the patera, the temperature is about -143 Celsius. Image Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM/MSSS “The high spatial resolution of JIRAM’s infrared images, combined with the favorable position of Juno during the flybys, revealed that the whole surface of Io is covered by lava lakes contained in caldera-like features,” said Alessandro Mura, the paper’s lead author. “In the region of Io’s surface in which we have the most complete data, we estimate about 3% of it is covered by one of these molten lava lakes.” Outstanding questions remain about the nature of Io’s volcanic activity and what happens underground. These new images help provide answers. The lava lakes have only a thin ring of exposed lava. There are no lava flows beyond the rim or inside the rim, which indicates a balance between the magma that erupted into the lake and the magma that flowed back underground. This figure from the research shows infrared radiance maps for six different paterae on Io. Each one has a lava ring inside the patera’s rim. Image Credit: Mura et al. 2024. “We now have an idea of what is the most frequent type of volcanism on Io: enormous lakes of lava where magma goes up and down,” said Mura. “The lava crust is forced to break against the walls of the lake, forming the typical lava ring seen in Hawaiian lava lakes. The walls are likely hundreds of meters high, which explains why magma is generally not observed spilling out of the paterae and moving across the moon’s surface.” The researchers proposed two different geologic models to explain the lava lakes in Io’s paterae: one they call a “central upwelling model” and the other a “piston motion” model. The central upwelling model explains that the insulating crust “spreads radially via convection processes in the lake and then sinks at the edges, exposing lava,” the authors explain in their research. Basically, heat rises in the patera’s center, pushes outward radially, and hot lava founders at the edge and is exposed. The problem with that model is the uniformity of the magma crust. JIRAM’s images show uniform heat across the magma crust, meaning it would have to be the same thickness. How could it maintain the same thickness while radiating horizontally? The piston motion is slightly different. In that model, “a simple up-and-down ‘piston-type’ movement of the entire lake surface may cause disruption of the lava lake crust against the patera walls to reveal hotter material,” the authors explain. There’s no radiating horizontal motion like the central upwelling; rather, the entire lake moves up and down. That model has problems, too. “For the piston-type lake model, the consistency between individual patera as well as the uniform brightness around the lake perimeter also poses geological challenges,” the authors explain. For all of the ten patera in the study to have hot rings of exposed lava, the vertical motion must be ongoing at all sites. At some sites, JIRAM should’ve detected changes in the depths of the patera. “No such depth changes at a specific patera have been reported,” the authors note, while also writing that the images may lack the temporal and spatial resolution to detect depth changes. This figure from the research shows the two models the researchers are proposing. On the left in A and B is the central upwelling model. On the right in C and D is the piston motion model. Image Credit: Mura et al. 2024. Activity at the rim where the lava is hottest may hold the eventual answer. “The observation of activity at the borders of the lake raises the question of whether some type of thermal or mechanical erosion between the lake surface and the patera walls might be taking place,” the authors write. Paterae might grow larger over time, but only by as much as a few hundred meters each year. No changes have been noted between visits by Voyager, Galileo, and Juno. It’s still possible, but the data is inconclusive. The Juno spacecraft may still be able to provide deeper answers to Io’s volcanic activity. It’s already completed closer flybys of Io, and that data will be available in the future. “Once the last Juno data are acquired, examining visible images of inactive patera for signs of former lava lake activity would be instructive,” the authors write in their conclusion. The post Volcanic Plumes Rise Above Lava Lakes on Io in this Juno Image appeared first on Universe Today.

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